0.5 ug/m3) and Low (<0.1 ug/m3) CNT/F exposures, 2,726 serum peptides significantly distinguish the groups. Of these, 41 are found to be highly discriminatory after model building and exhibit a strong linear correlation with personal CNT/F exposures. The top-five peptide model offers ideal prediction with high accuracy (Q2=0.99916). Unsupervised validation affirms 43.5% of the serum peptidomic variance is attributable to CNT/F exposure. Peptide sequence identification reveals a predominant association with vascular pathology. ARHGAP21, ADAM15 and PLPP3 peptides suggest heightened cardiovasculature permeability and F13A1, FBN1 and VWDE peptides infer a pro-thrombotic state among High CNT/F workers. The serum peptidome affords a diagnostic window into pre-symptomatic pathology among CNT/F exposed workers for longitudinal monitoring health risks.]]>